The internal cohort was retrospectively enrolled in West China Hospital, Sichuan University from June 2010 and December 2020. It is a training and internal validation cohort.

The same inclusion/exclusion criteria were applied for the same center prospectively. It is an external validation cohort.

We develop and validate clinical models to predict treatment responses and survival outcomes in patients with biopsy-proven with osteosarcoma.

The primary outcome was the evaluation of treatment response to individualized therapy in patients with osteosarcoma.

The endpoint was defined as the occurrence of progression or recurrence, or the last follow-up. Patients were followed from the day of histological diagnosis until the occurrence of progression or recurrence, or last visit. The outcome was evaluated by an experienced oncologist in each center every 3-6 months. At each visit, a medical history, physical examination, and standard laboratory tests were performed.

The endpoint was defined as the occurrence of death or the last follow-up. Patients were followed from the day of histological diagnosis until the occurrence of progression or recurrence or last visit. The outcome was evaluated by an experienced oncologist in each center every 3-6 months. At each visit, a medical history, physical examination, and standard laboratory tests were performed.